Process of increasing the ductility of metallic tungsten.



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UNITED STATES rArn OFFICE.

I WERNER VON BOLTON, OF CHARLOTTENBURG, GERMANY, ASSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROCESS OF INCREASING DUCTILITY OE METALLIC TUNGSTEN.

No Drawing.

fAccording to my invention the ductility of tun sten is increased by treating the metal igh temperature, preferably at red heat, with a halogen compound of an element of the sulfur .or phosphorous group. Hydrogen is added to this halogen compound. A m'xture of the vapors of protochlorid of sul ur with hydrogen is specially suitable. ,The chemical compounds subjected to the treatment, 6. 9., the tungstic acid which is still contained in the metal, or

which, without employing pure metal, can be employed as the sole starting material, are then for the most part converted into sulfid 'of tungsten. The chlorin whichfis liberated is at once bound to the hydrogen and thereby'the production of hybrids which can be disassociated only with very great difficulty is prevented. On the other hand, the

admixed hydrogen favorsthe .reduction and prevents the lnjurious formation of chlorids owing to thechlorin which is liberated. As

a final product a mass is obtained which substantially consists of sulfid of tungsten or of .metallic tungsten mixed with'sulfid of tungsten. In order" to obtain pure metallic tungsten of great ductility from this mass it is sufiicient to heat the masshighly in vacuo by passing through it an electric current.

If it is heated for example for some time to white heat while the air-pump is constantly working, a metallic mass which can, beat once drawn or rolled is obtained, whereas the metallic mass obtained by directly reducing tungstic acid by means of hydrogen has very materially less ductility. This less degree of ductility appears to be due to the resence of hydro en which can be expelled om tungstenon y at very high temperatures and when special precautionary measures are taken.

In order to favor the expulsion of the foreign matter, 6. g. sulfur, out of the metal and Snecification of Letters Patent.

Application filed September 18,1911. Serial No. 649,020.

the form of a not too thick rod or Patented Feb. 13, 1912.

at once to obtain bodies of a shape adapted to be worked up further, the starting material to be treated'is preferably brouht into lament which in roportion to its section has a large superficia area and can be readily connected to electrodes.

I claim 1. The process of increasing the ductility of metallic tungsten which consists in treating-metallic tungsten at a high temperature with a mixture of'hydrogen and a vaporizable halogen compound of sulfur, and in passing an electric current through the mass thereby obtained in an indifferent atmos'- phere and thereby expelling any sulfur from the said mam. i-

2. The process of securing metallic tungsten of good ductility which consists in heating the material to be converted into highly ductile. metal at a high temperature in the presence of hydrogen and a halogen compound of sulfur, and heating the resulting product in an inert envi onment and the'reby expelling the sulfur.

3. The process of increasing the'ductility" of metallic tungsten which consists'in treating tungsten at a high temperature with ya mixture of hydrogen and protochlorid of sulfur, and in passing: an electric current through the mass thereby obtained in 'an indifferent atmosphere and thereby expelling any sulfur from the said mass.

4. The process of securing metallic tungsten of good ductility consisting in treating the material to be converted into highly ductile metal ata high temperature with a halogen compound 0 sulfur to ether with a reucingagent which will un te with the halogen and prevent combination of the halogen with the tungsten, and heating the resulting product in an inert environment to eliminate an sulfur introduced by the treatment.

in testimony whereof I have signed my name to this specification in the presence of two witnesses. 1

' WERNER VON BOLTON.

Witnesses:

- Hnmzr HAsPnR,

' WOLDEMAR Ham. 

